Double skip lifting and transporting device



April 16, 1968 0. DOMENIGHETTI 3,373,153

DOUBLE SKIP LIFTING AND TRANSPORTING DEVICE Filed Feb. 14, 1966 2sheds-sheet 1 INVENTOR Domen'mo bomb Lghefii S aLn-Qw and 3 mm ATTORNEYSApril 16, 1968 o. DOMENIGHETTI ,378,

DOUBLE SKIP LIFTING AND TRANSPORTINC' DEVICE Filed Feb. 14, 1966 2Sheets-Sheet z INVENTOR Doman'mo Donal- E, gke

ATTORNEYS United States Patent 3,378,153 DOUBLE SKIP LIF'IING ANDTRANSPORTING DEVICE Domenico Domenighetti, 6 Via Nosetto, Bellinzona,Switzerland Filed Feb. 14, 1966, Ser. No. 527,282 Claims. (Cl. 214-103)ABSTRACT OF THE DISCLOSURE DOuble skip lifting and transporting devicein which there are coupled to a single winch two skips which slide upand down on the same rail means and there is provided at the middle ofthe path a double switch system allowing for the two skips to keepmoving in different directions without colliding.

In conventional building and road installations as well as in operativeworks for quarries, mines, cement factories etc., the equipment forconveying and lifting incoherent materials usually comprise means whichhave a rope attached to a skip unit sliding on variously inclined railmembers. The skip generally begins its movement from a starting stationin which it is charged with material e.g. crushed stone, in thisposition the winch rope being completely unwound. Actuation of the winchcauses the rope to wind up on the drum, whereby its length is reducedand the skip is pulled up to a certain end position in which thematerial is discharged usually by turning over the skip or opening adischarge port of same.

The operation of such an installation generally consists in thecontinuous repetition of the following steps:

starting of the skip from its charge position transfer of the skip up toits end station stopping of the skip in said end station and dischargetransfer back of the skip to its original starting position stopping ofthe skip in its original starting position and charge.

At the end of this last named operation the device is obviously ready tostart the first operation over again.

Thus, such a device is adapted to perform an operative cycle which maybe defined by its time of duration as well as by their number, should asuccession of cycles be required for carrying out a given work.

In more recent installations the actuation of the winch motor iscontrolled by automatic electro devices which are excited by theso-called endstroke means that indicate when the skip has reached itsend positions. In these modern installations also the charge anddischarge phases are controlled by automatic timing means which, after apredetermined time has passed, set the winch going again to have thedevice perform the successive operation. They may be also controlled byouter excitation impulses from external operations which are somehowrelated to the operative cycle of the installation to be driven.

For instance should the skip be charged by a feeder unit, it will bethis same feeder that indicates when the charge operation has beencompleted and that gives the impulse to the winch to have the skipstarted.

Independently from the driving and/or actuating system for the winch, itwill he obviously of the greatest importance that each operative cycleis as short as possible to allow for the largest possible number ofcycles per time and consequently for the transport of the largestquantity of material.

From a consideration of the various operations forming a cycle itclearly appears that, since the charge and discharge times for the skipscannot be reduced (as they ice depend from the nature of the material tobe transported as well as from other operative factors that areindependent from the lifting and transporting device) the only featurewhich may be improved is the displacement speed of the skip on the railsi.e. the winding time of the rope on the winch drum.

In the modern installations used for building and road constructionworks as well as in quarries, mines, cement factories and the like thisspeed is comprised between 2 and 2.7 ft./sec. (0.6 and 0.8 m./sec.) andmay reach the value of 3.3 ft./sec. (1 m./sec.) only under very specialand favourable conditions.

For avoiding too expensive embodiments (for instance variable speedwinches) one is compelled to take into consideration certain inertiaproblems at the starting and other considerable difficulties at theturning over of the skip, if the transfer speed should overcome theabove mentioned average values.

In the conventional installations for any given transport distance theduration of the cycle Was therefore set and could at the most beslightly reduced by increasing the transfer speed of the skip, whichhowever could eventually bring about many dangers such as a wear of theropes, vibrations, instabilities and so on.

Up to now the only solution to the problem of increasing the output wasto provide for two or more identical installations to work side by sideor to increase the capacity of the skip (and therefore the winch power).This last solution was however very expensive and not always desirablebecause it implied an increase of the overall dimensions.

It is the purpose of the present invention to drastically reduce theduration time of the cycle (less than half of the conventional time)while the length, and/or the heigth of the displacement path, thecapacity of the skip, the charge and discharge stations and the relativeoperations thereof and first of all the transfer speed of the skip arekept unvaried. This speed remains in fact below the critical values soas to ensure an easy and long life opera tion of the whole installation.

These important results as well as other advantages are achievedaccording to the present invention by coupling to a single winch, twoskips sliding up and down on the same rail means and by providing at themiddle of the path for a double switch system allowing for the two skipsto keep on moving in different. directions without colliding.

Conventional devices of this type (funicular railways etc.) usually haveswitch systems extending in horizontal and subhorizontal planes. Howeverthis kind of switch arrangements may not be easily utilized in thebuilding road or mine works or installations we are concerned with.

The double switch device of the present invention extends, on thecontrary in a vertical plane what brings about considerablesimplifications.

A particular non-limitative embodiment of said device will now bedescribed in detail by referring to the accompanying drawings, in which:

FIG. 1 is a diagrammatic elevation. of a conventional" device.

FIG. 2 is a diagrammatic elevation of a double skip device provided withthe switch system according to the present invention.

FIG. 3 is a perspective view of a kind of skip used according to thepresent invention.

FIG. 4 is a perspective view of an improved skip type according to thepresent invention.

FIG. 5 and 5' diagrammatically show a method of utilization of the twoswitch pairs according to the invention.

FIG. 6 is a diagrammatic view of a mechanical actuaion mechanism for theswitch system made to work by he very same weight of the skip.

The conventional lifting and transporting device as .hown in FIG. 1consists of the rail means 1 made of two J-shaped profile pieces havinga skip 2 moving thereon )y means of a pair of wheels 3 slidinglyreceived within raid U-shaped profile pieces while a pair of wheels 4are tupported by the upper wing portion thereof. The winch irum 5 hasthe towing rope 6 winding thereon and transnitted over the sheave orpulley 7 to be connected with he skip 2 over the auxiliary sheaves 8 and9. While the ope 6 winds up on the drum 5, the skip 2 is made to nountup the end station 10 which, in the case, also coresponds to thedischarge station. In face, due to a par- :icular conformation of therails before reaching said :nd station the skip is made to turn upsidedown thereby iischarging the contained material from its upper out- )ut11.

An embodiment of the device of the invention is illus- :rated in FIG. 2wherein two skips are provided. The ;kip 2 is at the starting station,the skip 12 at the end and discharge station 10. The tow rope 6 iscontinuously driven to wind up on the drum 5. A branch 6 is deviatedaver the transmission sheave 7 to reach the skip 2 while :he otherbranch portion 13, which is also deviated over :he sheave 7, isconnected with the skip 12 over the pulieys 14 and 15. As a consequenceof the station of the drum 5 in one direction the ropes pull on the skip2 to have it move from the starting station to the end station 10 andcontemporaneously act upon the skip 12 to have it move from the endstation 10 to the starting station. Opposite rotation of the drum 5causes opposite displacements of the skips. Since both the skips move onthe same rails 1 they would collide at the middle of their path, shouldno special means be provided to avoid it, this :ollision is prevented byprovision of a rail switch system according to the invention whichconsists in a branching off the rails to form two separate branchpositions 16 and 17. The branch 16 always has the skip 2 and the branch17 always has the skip 12 sliding thereon.

According to the invention there are two switches 18 and 19 eachcomprising a plurality of blades mechanically interconnected andactuated by a cam projecting from one of the two skips. These skipsassume on the branches 16 and 17 respectively the positions 20 and 21,i.e. they move one over the other in a vertical plane without evercolliding. In fact, the central space between the rails is free and theside support wheels of the skips are guided by the switches to followeach its own path.

In FIG. 3, a skip comprising a tub unit or hopper 22 is mounted on axles23 and 24 the ends of which are adapted torespectively receive the backwheels 4 and the front Wheels 3. These last named wheels slide withinthe U- shaped profile pieces forming the rails while the wheels 4 slideon the upper wing portion of said profile pieces. To transmit thepulling force of the rope 6, which in the case of FIG. 3 works with adouble pull action there is provided a sheave 25 mounted on a drawstirrup 26, the arms of which are pivotedly mounted in the skipsupports, while possible oscillations of said stirrup are controlled bytwo rollers 27 resting on the rails 1.

In the embodiment of FIG. 4, the skip with its hopper 22 is also mountedon axles 23 and 24, the ends of which are adapted to respectivelyreceive the wheels 4 and 3. In this case, however the rope 6 which alsoexerts a double pulling action, engages the hopper 22 over a pair ofsheaves 9 with substantially horizontal rotation axis as well as overpair of sheaves S with substantially vertical axis. Each sheave 9 isalmost tangential to the adjacent sheave 8 so that the rope may easilypass underneath the hopper 22 to reach then the fixed end 28 of thetowing rope 6. A switch system is shown in FIG. 5 with four blades 29,30, 31 and 32 respectively pivoted in 29, 30, 31' and 32. This switchcorresponds to the position in which the rail 1 branches oif to form thetwo portions 16 and 17. When the blades are in the position shown inFIG. 5 the skip passes from the rail 1 to the branch 17 since the wheels3 are well as the wheels 4 are free to slide in such a direction. Thetwo closely fittting blades 30 and 32, the free ends of which rest onthe respective pivots 32' and 30 prevent the wheel 4 on its way up ordown from stressing or damaging the switch, even though every wheelusually exerts a considerable stress with component normal to itsrolling plane. Similar considerations may be made with regard to thewheels 3. In this case however the normal stresses may be easily removedby the blades 29, 31 and 32, the free ends of which rest on fixed point.

By simultaneously rotating all blades of an angle equal to the oneexisting between the branch portions 1 6 and 17, one comes to theposition shown in FIG. 5' in which the skip is made to slide first onthe rail 1 and then on the branch 16 or vice versa. In fact, theposition of the blades leads the wheels 3 and 4 to follow the dashedpaths 33 and 34.

FIG. 6 shows the back portion only of a mechanical control mechanism forthe switch system of FIGS. 5 and 5. The pivots 29, 36, 31 and 32' refixed to just as many control levers 29", 3G", 31 and 32" which are intheir turn connected to linking rods 35, 36 and 37. The linking rod 37extends to form a mobile rail 38 which is actuated for instance bypressure of a cam 39 coaxially mounted with respect to the wheels 4. Bycontacting the rail 38, the cam 39 imparts thereto a motion having acomponent 40 a direction transverse to the rail 1. This transversecomponent causes the contemporaneous rotation of 'all the levers 29",30", 31 and 32" of a same angle and therefor a correspondentdisplacement of all the blades, which hence move from the position ofFIG. 5' to the one of FIG. 5. When the cam 39 releases the rail 38, areturn spring 41 will bring the switch back to the position of FIG. 5.

What is claimed is:

1. A main trackway having its lower and upper ends horizontally andvertically spaced from each other, a secondary trackway substantiallyshorter than the main trackway and having entrance and exit endscommunicating with the main trackway intermediate the ends of thelatter, switch means at the said exit and entrance ends, a pair ofskips, power drive means interconnecting the skips for equal andopposite movements relative to each other such that when one skip isascending the other skip is descending whereby one skip bypasses theother skip by the secondary trackway, means to cause tilting and dumpingof the skips at the upper end of the main trackway, a skip loadingstation at the lower end of the main trackway, and means on one of theskips to engage and operate the switch means.

2. The device as claimed in claim 1, and in which each of said skips isprovided with two pairs of sheaves respectively rotating on axes whichare substantially perpendic ular to each other and with theirperipheries arranged to be tangential to each other two by two so thatthe rope passing on said two sheave pairs may freely slide in adirection perpendicular to the sheave axis, whereby allowance is madefor said skip to swing as required about an horizontal axis especiallyduring the turning upside down of said skip in the discharge phase ofsame.

3. The device as claimed in claim 1, and in which each of said skips isprovided with a drawing stirrup pivotally 5% closely fitting to eachother so that the free end of one blade rests substantially on the pivotof the other blade, whereby the transverse stresses due to the skipWheel are effectively resisted upon independently of the direction theycome from.

5. The device as claimed in claim 4, and wherein the rotation pivots ofsaid four blades are each provided with levers of equal length andparallel to each other, said levers being connected at their ends withlinking rods, at least one of Which extends forming a mobile railportion controllable by a cam mounted on one of said skips.

6 References Cited UNITED STATES PATENTS 730,799 6/1903 Rust 214-41 5260,324 6/1882 Rockwell 214-1l 334,076 1/1886 Kitto et a1 214-1( GERALDM. FORLENZA, Primary Examiner.

10 R. B. JOHNSON, Assistant Examiner.

